1. Field of the Invention
The present invention relates to an image registration device, method, and non-transitory computer readable medium storing a program for performing registration between a target object included in a video and a simulation image relevant to the target object.
2. Description of the Related Art
In recent years, surgical simulation using a three-dimensional medical image has been actively performed. Surgical simulation is for visualizing surgery target tissue, organs, and surrounding structures thereof in a medical image and simulating the procedure performed in actual surgery. For example, in a partial resection simulation of the liver, a simulation image viewed from the operative field at the time of surgery is generated by extracting tissues, such as the liver, the portal vein, veins, arteries, the body surface, bone, and a tumor, from a computed tomography (CT) image or a magnetic resonance imaging (MRI) image and visualizing the tissues as a three-dimensional image. Then, a range for excising a tumor in the liver is calculated by a computer using the simulation image, and a surgical plan is made to perform the surgery.
On the other hand, there is a desire to see the simulation image during surgery. For this reason, paper on which a simulation image is printed is brought to the operating room, or the simulation image is displayed on a display installed in the operating room. Then, a doctor performs the surgery while watching the operative part of the actual patient and while viewing the simulation image printed on paper or displayed on the display for the sake of confirmation.
However, it is very troublesome to perform the surgery while alternately viewing the patient and the simulation image. Therefore, a method of acquiring a video including a plurality of images by imaging a surgery target part during surgery and displaying a simulation image so as to be superimposed on the video has been proposed. For example, JP2013-202313A has proposed a method of attaching an optical sensor or a magnetic sensor directly to a camera for imaging an operative part, a surgical instrument, or an organ, performing a calibration, that is, initial registration of the relative positional relationship therebetween, registrating a surgery target part and a simulation image by moving the simulation image with respect to changes in the position and orientation of the camera and the movement of the organ after the initial registration, and displaying the surgery target part and the simulation image after the registration so as to be superimposed on each other.
In addition, a method of placing a marker in a surgery target part, detecting the position of the marker using a sensor, registrating the surgery target part and a simulation image, and displaying the surgery target part and the simulation image after the registration on a head mounted display (refer to JP2010-259497A) and a method of embedding a marker in a surgery target part, detecting the marker using a sensor, registrating the surgery target part and a simulation image, and displaying the surgery target part and the simulation image after the registration on a monitor (refer to JP2010-200894A) have also been proposed.
On the other hand, a method of registrating an image of a patient who has been captured and a simulation image without using a sensor or the like has also been proposed. For example, JP2012-205899A has proposed a method in which, when generating an organ model from a three-dimensional image and displaying the organ model so as to be superimposed on an ultrasound image in real time, an affine transformation function between each frame of the ultrasound image and the organ model is calculated, the organ model is converted based on the affine transformation function, and the converted organ model is superimposed on the ultrasound image. JP2012-518520A has proposed a method of performing registration between an image of the bone and a template configured to include the contour of the bone. JP2007-268259A has proposed a method of performing registration between the wire-frame model of a three-dimensional image and a target object. JP2008-068086A has proposed a method of performing registration between an ultrasound image and a contour model by superimposing the contour model on the ultrasound image.